Updated and retrospective estimates of shortfin mako (Isurus oxyrinchus) landings by the spanish surface longline fishery targeting swordfish in areas of the Atlantic Ocean during the 1950-2015 period.

Abstract

Landings of shortfin mako (Isurus oxyrinchus) by the Spanish surface longline fleet targeting swordfish in Atlantic areas were estimated for the period 1950-2015 combining different sources of information. An approximation to the magnitude of landings during the 1950-1982 period was estimated by the retrospective application of the ratio between shortfin mako and the target species (swordfish) landings observed at the beginning of the 1980s in this fishery. Landings for the period after 1982 were estimated either by reports available in literature for some of the years or by means of trip reports for the periods in which data were not previously available. A new data set was generated for the nine-year period 1988-1996 applying a data mining approach to trips during that period. Additionally, a revision of the Task I data available in the ICCAT data base 1997-2015 was carried out. Information from all these sources was combined to propose a new set of figures for landings by stock. The authors recommend using post-1982 estimates for stock assessment.

Landings of shortfin mako (Isurus oxyrinchus) by the Spanish surface longline fleet targeting swordfish in Atlantic areas were estimated for the period 1950-2015 combining different sources of information. An approximation to the magnitude of landings during the 1950-1982 period was estimated by the retrospective application of the ratio between shortfin mako and the target species (swordfish) landings observed at the beginning of the 1980s in this fishery. Landings for the period after 1982 were estimated either by reports available in literature for some of the years or by means of trip reports for the periods in which data were not previously available. A new data set was generated for the nine-year period 1988-1996 applying a data mining approach to trips during that period. Additionally, a revision of the Task I data available in the ICCAT data base 1997-2015 was carried out. Information from all these sources was combined to propose a new set of figures for landings by stock. The authors recommend using post-1982 estimates for stock assessment.